1. Field of the Invention
The invention relates to an adapter for use in attaching tool heads to fiberglass tool handles and for making other fiberglass attachments and connections.
2. Description of the Prior Art
This invention is an improvement upon the structure disclosed in my prior U.S. Pat. Nos. 3,753,602 and 3,819,288.
A fiberglass composite used for a handle shaft which provides the optimum performance characteristics due to its composition, i.e. a fiberglass shaft with all glass fibers in tension, continuous and parallel, does not offer a high level of compressive strength compared to tool heads which are predominently of hardened steel.
It has been found that when the handle shaft and the tool head are assembled in the field by driving the tool head onto the adapters which are attached to the handle shaft or by driving the handle with its attached adapters into the eyehole of the steel head, a wide range of force will be used by the average installer, who would virtually never have a means of measuring how much force he is applying. It is this force in an impact mode which is exerted on the handle shaft and adapter assembly, with extremely high loads when this impact is delivered on a solid surface such as concrete or a steel block.
Where variations in eyehole size are accommodated on the major axis by spacers but not on the minor and, to achieve the compressive forces on the handle shaft to assure permanent attachment (which by definition must provide that the two halves of the adapters not meet or bear on each other), full reliance is on the shaft in regard to compressive strength.
It has been found that overly zealous workers in the field have applied excessive compressive force against the major axis sides of the end of the fiberglass shaft, thereby delaminating it and causing the entire assembly to fail.
It has also been found that proper alignment of a plurality of parts having varying tolerances has been difficult to achieve.